Nomograms for predicting annual resolution rate of primary vesicoureteral reflux: results from 2,462 children

Abstract

Purpose: We determined the resolution rate of vesicoureteral reflux and the factors that influence it to formulate nomograms to predict the probability of annual resolution for individual cases of reflux.

Materials and methods: We studied 2,462 children with primary vesicoureteral reflux diagnosed between 1998 and 2006. Cox proportional hazards regression was used to model time to resolution as a function of statistically significant demographic and clinical variables. The resulting model was used to construct nomograms predicting the annual cumulative probability of reflux resolution.

Results: Multivariate analysis showed that all cases of unilateral reflux resolved earlier than female bilateral reflux (HR 1.42, p <0.001). Additionally age less than 1 year at presentation (HR 1.31, p <0.001), lower reflux grade (2.96, p <0.001 for grade I; 2.28, p <0.001 for grade II; 1.63, p <0.001 for grade III), reflux diagnosed on postnatal evaluation for prenatal hydronephrosis or sibling screening (1.24, p = 0.002) and single ureter (1.55, p <0.001) were associated with significantly earlier resolution of reflux. Specific predicted cumulative probabilities of reflux resolution at annual intervals from diagnosis (1 to 5 years) were calculated for every possible combination of the significant variables.

Conclusions: Our analyses demonstrate that resolution of vesicoureteral reflux is dependent on age at presentation, gender, grade, laterality, mode of clinical presentation and ureteral anatomy. We constructed nomogram tables containing estimates of annual reflux resolution rate as a function of these variables. This information is valuable for clinical counseling and management decisions.